boards: ti/mspm0: add support for L2228 launchpad

MSPM0L2228 launchpad provides evaluation and development
platform with 32KB SRAM and 256KB Flash. This board also
comes with 32Mhz external high frequency crystal and 32.768Khz
low frequency crystal.

Also LCD (only with L2228 SoC's) is included with many multi-function
PIO's exposed. Add support with basic UART and LED functions.

Signed-off-by: Parthiban Nallathambi <parthiban@linumiz.com>